Cat C Bike

Got a problem,

When you first apply the front brake it comes closer to the bar than it does on the second application, and if you roll the bike back n forth a bit it seems to do it then,I've bled the hell out of them and its still doing it

Warped disc?Or impact damage to the disc? Can't feel any pulsing when braking though
 
wazza300 said:
Got a problem,

When you first apply the front brake it comes closer to the bar than it does on the second application, and if you roll the bike back n forth a bit it seems to do it then,I've bled the hell out of them and its still doing it

Warped disc?Or impact damage to the disc? Can't feel any pulsing when braking though
Click to expand...

That's so weird! I currently have 100% that exact issue on my Speed Triple. When you first use the front brake, it comes closer to the bar, then after that it's fine for a bit. It's almost as if the pistons are retracting when not in use for some reason as it feels a bit like after you've bled and pump it to get them out again.

My issue started as soon as I put my stubby levers on, so hopefully it's just something weird going on with those. I have put my old levers back on now to see if it continues.

Guess I'll just bleed and try fix it that way if the lever isn't the issue. And if that doesn't fix it, then I'll just mention it in the service I've got in a couple of weeks and they can look.

I wonder if this sort of thing would be covered under the warranty...
 
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Yeah should be,I'd ring and ask, might need a really good bleed the mechanic said radial master cylinders are funny

It's holding me up now,he won't pass it till I fix it n I've tried all I can think of,I'm gonna get the front end up tommorrow and check best I can for disc runout
 
wazza300 said:
Yeah should be,I'd ring and ask, might need a really good bleed the mechanic said radial master cylinders are funny

It's holding me up now,he won't pass it till I fix it n I've tried all I can think of,I'm gonna get the front end up tommorrow and check best I can for disc runout
Click to expand...

Yeah I'll give them a ring tomorrow if they're open, or on Tuesday if it wasn't the lever causing it. If it is something they can sort in warranty, I'll just get them to look at service time. Don't really want to do my Scotland trip with a weird front brake, after a run down the motorway it tends to then need pulling back further, so not good if I had to stop in a hurry on the motorway.

Have you tried the trick where you tie the brake lever overnight on yours?
 
Yeah it seemed to improve it a little but it was still there,he failed it again today,I might try longer with the zip tie
 
Can't you squeeze it a few times before it actually goes in for the test? At least if he thinks it's fixed, you can get it on the road and can sort it whenever?
 
He rides it and tests it,I can't feel it when I'm riding tbh

The ironic thing is a had an old banger that passed every time with worse brakes and this newer bike fails,first fail I've had since 125cc days
 
Oh right, that's a bit thorough if he takes it out for a ride! My local MOT tester just sticks it on a brake testing machine, it's like a mini, slow rolling road thing that just tells you how effective your brakes are.

I'd also take it elsewhere, unless he's doing free retests.
 
Yep just take it wherever you like you'll have to pay for the retest elsewhere though.

I've never heard of an MOT tester taking anything out for a road test to be honest.
 
wazza300 said:
Got a problem,

When you first apply the front brake it comes closer to the bar than it does on the second application, and if you roll the bike back n forth a bit it seems to do it then,I've bled the hell out of them and its still doing it

Warped disc?Or impact damage to the disc? Can't feel any pulsing when braking though
Click to expand...


That symptom is typical of air in the brakes. If you keep pumping the lever quickly you'll probably find the bite point moves out even further.

Try reverse bleeding, if you've not already.
 
Dogbreath said:
That symptom is typical of air in the brakes. If you keep pumping the lever quickly you'll probably find the bite point moves out even further.

Try reverse bleeding, if you've not already.
Click to expand...

Any idea why it seems to it when I push the bike back or forward a little? Stationary its firm

I might let them bleed it,messing on bikes does my head in sometimes:(
 
wazza300 said:
Any idea why it seems to it when I push the bike back or forward a little? Stationary its firm
Click to expand...

Sorry I missed that bit. If the pads are getting knocked back then there more expensive possibilities:

1) Brake disc is warped (or possibly not bolted down squarely)
2) Caliper mount bent.

Do you get any pulsing under braking at slow speeds? If the braking feels perfectly smooth then suspect a caliper mount (i.e. fork lower), it's quite easy for them to get bent in an accident and it only takes a tiny bit to ruin the feel since the pads aren't contacting the disc perfectly square. If you push the bike forward and back and then apply the brake, do you see the disc move much?

The GSX-R1000 forks I was going to use on my Blade had one caliper mount bent, fortunately I found it when measuring up to make spacers for the calipers.
 
No pulsing under braking,the fork was ever so slightly bent and he straightened it,only thing that was broken off was the mudguard mounting tab which I had welded back on

Idk if the caliper mounts bent of not,but the fork leg supposed to be straight now
 
Just finished cleaning and re-bleeding mine. Seems to be better, but only riding will tell. Hopefully not a warped disc here either - that could get expensive! Doesn't go spongy after just wheeling it now though which is good. So mine was either a bit of a sticky piston, or air in the system somehow. I'd lean towards sticky piston as I can't see how air would have got in.
 
I hope you've cured it

It's doing my nut in,mine ain't spongy they are sharp every time it's just the lever comes back a few mm further every now n then,to me it's trivial as I've got really good braking still but I'm not the mot man
 
Took the brake caliper off the side it had the impact and packed it up,then rolled it and applied the brake,no lever movement so maybe it's a bent disc? Pushing the pads in slightly
 
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